Clamshell and other bucket gear



Sept. 12, 1939. G RUST 2,172,891

CLAMSHELL AND OTHER BUCKET GEAR Filed Dec. 17, 1958 Gait/a7: Farsi.

Patented Sept. 12, 1939 UNETED STATES PATENT OFFICE 2,172,891 7 CLAMSHELL AND OTHER BUCKET GEAR Gordon M. Rust, Philadelphia, 1 4.-

Application December 17, 1938, Serial No. 246,267

1 Claim.

The present invention relates to improvements in clam shell buckets of the type operated from two drums by means of two cables, a holding cable and a hoisting or closing cable. The hoist- 5 ing or closing cable'is so connected with the bucket that it is operative to close the clam shells. When the bucket is supported by the holding cable the clam shells open by gravity. The

hoisting drums are connected or disconnected 10' manually with the same driving mechanism so that when connected they run at the same speed and when either of them is disconnected there is a drum brake which opposes overrunning. The bucket is lowered by the holding cable and 15 the hoisting or closing cable runs free but does not overrun. By gravity the clam shells or jaws are opened and the bucket is lowered on to, for example, a coal pile which supports its weight. Then the drum of the hoisting or closing cable 20 is connected with the driving mechanism and the clam shells or jaws are closed while the weight of the bucket is supported by the coal pile. At the beginning of the lift both the holding cable and the hoisting or closing cable are hauled in 25 at the same speed because each of their drums is connected with the driving mechanism and in that way the bucket and its load are lifted from the round, the weight thereof being carried by the two cables. Sometimes it happens that a 30 piece of foreign matter as coal is caught between the abutting jaws of the clam shells and holds them open so that when the bucket and its load are lifted the jaws are not tightly closed and coal or other material spills out of the bucket and is 35 lost. In the case of unloading coal from barges the coal which spills out of the bucket in that way falls into the water and is lost and also reduces the depth of water which interferes with the draft of the barges.

4 The principal object of the present invention is to obviate the above mentioned. difficulty and to provide automatic means for exerting additional force tending to close the clam shells and cut away the object caught between and opposes 45 their closing movement at the beginning of the lift of the bucket and its load.

Other objects of the invention will appear from the following description at the end of which the invention will be claimed.

50 Generally stated the invention consists in a spring limit stop device interposed in the holding cable and adapted to yield to a limited extent under the weight of the load and of the bucket at the start of the lift so that substantially the 55 entire weight of the load and bucket is on the closing cable which tends to close the clam shells against the resistance of an object accidentally caught between them thereby usually cutting the object away with the result that the bucket drops slightly and the spring device takes up the recoil, it being understood that at the beginning of the lift both the holding cable and the hoisting or closing cable are traveling at the same speed because their drums are connected with the driving mechanism.

The invention also consists in the improvements to be presently described and finally claimed. 4 V

In the following description reference will be made to the accompanying drawing forming part hereof and in which,

Figure 1 is an elevational View partly in section illustrating a clam shell bucket having my invention embodied therein.

Fig. 2 is a diagrammatic view illustrating the bucket after it has been positioned on the coal pile with its clam shells in open position.

Fig, 3 is a similar view showing the bucket closed by a pull on the hoisting or closing cable and indicating that an object has been caught between its jaws, and

Fig. 4 is a similar View showing both cables running in unison at the beginning of the lift and indicating that the holding cable has been elongated thus throwing the entire weight of the bucket and its load, now clear from the support or" the coal pile, on the hoisting or closing cable with the result that the object caught between the clam shells has been fractured.

Referring to the drawing the spring limit stop device is shown to comprise two elements I and 2, having interposed between them a normally expanded spring 3. This limit stop device is interposed in the holding cable 4. 5 indicates the hoisting or closing cable and b indicates the 40 jaws of the clam shells of the bucket. The construction is such that when the hoisting or closing cable 5 is not connected with the driving means but is loose or slack the clam shells open. and the bucket is lowered by the holding cable 4 with the parts of the limit stop device in the positions indicated in Fig. 1 on to the coal pile. This is indicated in Fig. 2. The operator now connects the drum 5 of the hoisting or closing cable 5 with the driving mechanism, the drum l of the holding cable 4 is not connected with the driving mechanism. The result of this is that the cable 5 and drum 5 close the jaws or clam shells. The only resistance to the force exerted to produce this closing movement is the weight of the bucket and its load. It sometimes happens that the object as a is caught between the jaws b of the bucket as shown in Fig. 3, and that this object resists the force of the closing movement of the jaws which is limited by the weight of the bucket and its load as has been stated.

The next operation is the lift of the bucket and its load and that is illustrated in Fig. 4. At the beginning of the lift both cables 4 and 5 are running and the cable 5 is carrying substantially the weight of the bucket and its load, whereas in Fig. 3 the weight of the bucket and its load was supported by the coal pile. The weight of the bucket and its load is such that the spring 3 is compressed which has the effect of elongating the cable 4 causing it to bear practically none of the burden. The hoisting or closing cable 5 has upon it substantially the whole of the weight of the bucket and its load with the result that there is exerted a force tending to close the jaws b of the clam shells. This closing force is sufficient to cut through or pulverize the object a so that the clam shells are really closed. When the object a escapes, the jaws come together and the bucket drops slightly and the spring 3 takes up the recoil. Thereafter both cables 4 and 5 jointly operate to further lift the bucket and its load clear of the coal pile, it being understood that both cables are running at the same speed.

Of course the result above described can be accomplished by connecting the drums and the driving mechanism at proper intervals in the lift of the bucket and its load from the coal or other support but with standard apparatus the drums are connected and disconnected with the driving means manually by an attendant usually located where the under side of the bucket as it is lifted from the coal pile is'not visible. By the present invention this result is accomplished automatically and with certainty which is an important feature of the invention.

It will be obvious to those skilled in the art to which the invention relates that modifications may be made in details of construction and arrangement without departing from the spirit of the invention which is not limited as to such matters or as to matters of mere form or otherwise than the prior art and. the appended claim may require.

I claim:

In a clam shell bucket having a single reach of holding cable and a single reach of closing cable and two drums which cooperate at the same speed at thestart of the lift of the weight of the previously closed bucket and its load, the combination of a spring limit stop device interposed in the holding cable only and adapted to elongate to a limited extent under the weight of the load and of the bucket as they clear the ground whereby substantially the entire weight of the load and bucket is on the closing cable which tends to cause the clam shells to close against the resistance of an object accidentally caught between them so that the object is cut and the jaws closed and the bucket dropped slightly whereupon the spring device takes the recoil.

GORDON M. RUST. 

